The present invention relates to a novel fluoroalkyl acrylate copolymer and its use, and more particularly to a fluoroalkyl acrylate copolymer curable with a light or energy ray and a sensitive composition containing the copolymer.
Hitherto, it is known that a hompolymer having recurring units of the general formula (I): ##STR3## wherein R.sub.1 is hydrogen atom or methyl group, R.sub.2 is a bivalent hydrocarbon group, and R.sub.f is a C.sub.2 to C.sub.6 straight or branched perfluoroalkyl group or a C.sub.2 to C.sub.6 straight or branched fluoroalkyl group having hydrogen atoms of not less than one and of not more than half of the number of the carbon atoms,
forms a film having a low surface energy, thus having a water-repellent property and can be used as water-repellent coatings. Also, the homopolymer has a sensitivity to far ultraviolet rays having a wavelength of not more than about 3,000 angstroms, electron beams and X-rays to undergo degradation, and is useful as a resist of positive type in which the irradiated portion of the film is dissolved by a developer and the unirradiated portion is left undissolved.
However, this homopolymer film has a defect of having poor strength and poor adhesiveness to a substrate, and it is necessary to treat at high temperatures in order to reduce such a defect. Further, this homopolymer has no sensitivity to near ultraviolet rays having a wavelength of about 4,000 to about 3,000 angstroms, and also in the case where the homopolymer resist is irradiated even by far ultraviolet rays, electron beams or X-rays, the remaining unirradiated portion of the resist is poor in adhesiveness and the homopolymer film is not suitable particularly for producing a fine pattern.
It is an object of the present invention to provide a novel copolymer sensitive to a light and energy ray.
A further object of the invention is to provide a polymer curable by radiation of a light or energy ray.
A still further object of the invention is to provide a light and energy ray curable polymer capable of giving a film having good film strength and good adhesiveness and sufficient water and oil repellent properties.
Another object of the invention is to provide a light and energy ray sensitive composition.
These and other objects of the invention will become apparent from the description hereinafter.